For shihonage what has always worked best for me to keep my hands in the proper alignment is to essentially glue them to my forehead as I enter and turn.
To make sure I have uke's balance before entering and turning, I put my "free" hand at uke's elbow and gently turn it away until uke rises from his center.
It seems I tend to raise my hands, and Ukes as I turn...I suppose I do this as it feels awkward for me to squat under them as I turn.
(I feel Im loosing balance - my legs are not the strongest part of me)
Hopefully that made sense.